1. Field of the Invention
This invention pertains to the field of smoking materials. More particularly, the present invention concerns a method for preparing a smoking material with reconstituted tobacco having incorporated therein fine tobacco dust.
2. Description of the Prior Art
As a result of treating, handling and shipping tobacco in its various forms, i.e., cigar wrappers or fillers, cigarets, smoking tobacco, etc., tobacco dust is generally formed. This dust, generally less than about 60 mesh in size, is recovered from air filters, tobacco screens and other like separating systems. Generally, it has been desirable to employ this tobacco dust in conjunction with other tobacco by-products, such as stems, stalks and leaf scraps resulting from the stripping of leaf tobacco, in the preparation of reconstituted tobacco material.
One process for making reconstituted tobacco sheets involves casting or forming a paste or slurry of refined tobacco by-products, including dust, onto a moving belt. In such a technique, the employment of very fine tobacco particles is feasible inasmuch as these tobacco dust particles are simply retained on the moving belt, present no manufacturing difficulties are not lost during the sheet formation. This is not, however, true in a paper-making type process for the preparation of reconstituted tobacco.
More particularly, when employing a paper-making process for preparing reconstituted tobacco, the tobacco dust must generally be discarded or employed elsewhere. This is due to the fact that in the paper-making process, the slurry of refined tobacco by-products is cast from a head box onto a wire screen for forming the desired sheet. If the screen mesh size is too large, the dust particles simply pass through the wire screen and do not, as a result, become incorporated in the resulting sheet. Conversely, when the screen mesh size is reduced so as to prevent the tobacco dust particles from passing therethrough, the dust considerably slows the drainage of the water through the screen and correspondingly slows the rate of sheet formation by actually plugging and/or clogging the wire screen openings.
Accordingly, although the paper-making type process for making reconstituted tobacco material has many advantages over the alternative casting/moving belt method, particularly, in that a binder is not required to hold the fibers together and a significant amount of solubles can be removed from the tobacco material to be treated separately and later reincorporated in the resulting sheet, and is consequently the preferred method, it nevertheless does suffer from the disadvantage of not being able to efficiently and conveniently employ tobacco dust by-product. A means for employing tobacco dust in such a process is described in copending application Ser. No. 223,035 assigned to the assignee of the present application, but that means is somewhat complex and consequently more costly than that about to be disclosed.